feat: add span level measurements #1855 (#2214)

* feat: add span level measurements

* add changelog entry

* add issue link to changelog

* fix: correct changelog

* moved the stored measurements from root span to tracer

* changed issue number to pr number in changelog

* fixed formatting

* Update CHANGELOG.md

Co-authored-by: Giancarlo Buenaflor <giancarlobuenaflor97@gmail.com>

---------

Co-authored-by: Martin <martin@haintz.dev>
Co-authored-by: Giancarlo Buenaflor <giancarlobuenaflor97@gmail.com>

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+### Features
+
+- Add support for span level measurements. ([#2214](https://github.com/getsentry/sentry-dart/pull/2214))
+
 ## 8.6.0
 
 ### Improvements

dart/lib/src/protocol/sentry_span.dart

@@ -242,7 +242,12 @@ class SentrySpan extends ISentrySpan {
     num value, {
     SentryMeasurementUnit? unit,
   }) {
-    _tracer.setMeasurement(name, value, unit: unit);
+    if (finished) {
+      _hub.options.logger(SentryLevel.debug,
+          "The span is already finished. Measurement $name cannot be set");
+      return;
+    }
+    _tracer.setMeasurementFromChild(name, value, unit: unit);
   }
 
   @override

dart/lib/src/sentry_span_interface.dart

@@ -71,7 +71,7 @@ abstract class ISentrySpan {
   /// Returns the trace information that could be sent as a sentry-trace header.
   SentryTraceHeader toSentryTrace();
 
-  /// Set observed measurement for this transaction.
+  /// Set observed measurement for this span or transaction.
   void setMeasurement(
     String name,
     num value, {

dart/lib/src/sentry_tracer.dart

@@ -17,7 +17,9 @@ class SentryTracer extends ISentrySpan {
   late final SentrySpan _rootSpan;
   final List<SentrySpan> _children = [];
   final Map<String, dynamic> _extra = {};
+
   final Map<String, SentryMeasurement> _measurements = {};
+  Map<String, SentryMeasurement> get measurements => _measurements;
 
   Timer? _autoFinishAfterTimer;
   Duration? _autoFinishAfter;
@@ -320,10 +322,6 @@ class SentryTracer extends ISentrySpan {
   @override
   SentryTraceHeader toSentryTrace() => _rootSpan.toSentryTrace();
 
-  @visibleForTesting
-  Map<String, SentryMeasurement> get measurements =>
-      Map.unmodifiable(_measurements);
-
   bool _haveAllChildrenFinished() {
     for (final child in children) {
       if (!child.finished) {
@@ -341,10 +339,19 @@ class SentryTracer extends ISentrySpan {
   @override
   void setMeasurement(String name, num value, {SentryMeasurementUnit? unit}) {
     if (finished) {
+      _hub.options.logger(SentryLevel.debug,
+          "The tracer is already finished. Measurement $name cannot be set");
       return;
     }
-    final measurement = SentryMeasurement(name, value, unit: unit);
-    _measurements[name] = measurement;
+    _measurements[name] = SentryMeasurement(name, value, unit: unit);
+  }
+
+  void setMeasurementFromChild(String name, num value,
+      {SentryMeasurementUnit? unit}) {
+    // We don't want to overwrite span measurement, if it comes from a child.
+    if (!_measurements.containsKey(name)) {
+      setMeasurement(name, value, unit: unit);
+    }
   }
 
   @override

dart/test/sentry_span_test.dart

@@ -310,6 +310,21 @@ void main() {
     expect(fixture.hub.options.enableSpanLocalMetricAggregation, false);
     expect(sut.localMetricsAggregator, null);
   });
+
+  test('setMeasurement sets a measurement', () async {
+    final sut = fixture.getSut();
+    sut.setMeasurement("test", 1);
+    expect(sut.tracer.measurements.containsKey("test"), true);
+    expect(sut.tracer.measurements["test"]!.value, 1);
+  });
+
+  test('setMeasurement does not set a measurement if a span is finished',
+      () async {
+    final sut = fixture.getSut();
+    await sut.finish();
+    sut.setMeasurement("test", 1);
+    expect(sut.tracer.measurements.isEmpty, true);
+  });
 }
 
 class Fixture {

dart/test/sentry_tracer_test.dart

@@ -467,6 +467,22 @@ void main() {
       expect(fixture.hub.options.enableSpanLocalMetricAggregation, false);
       expect(sut.localMetricsAggregator, null);
     });
+
+    test('setMeasurement sets a measurement', () async {
+      final sut = fixture.getSut();
+      sut.setMeasurement("test", 1);
+      expect(sut.measurements.containsKey("test"), true);
+      expect(sut.measurements["test"]!.value, 1);
+    });
+
+    test('setMeasurementFromChild does not override existing measurements',
+        () async {
+      final sut = fixture.getSut();
+      sut.setMeasurement("test", 1);
+      sut.setMeasurementFromChild("test", 5);
+      expect(sut.measurements.containsKey("test"), true);
+      expect(sut.measurements["test"]!.value, 1);
+    });
   });
 
   group('$SentryBaggageHeader', () {